What is the link between Nazis, propaganda, SA and the role of hitler?

Hitler was the leader of the Nazi party (translated in english as the National Socialist German Workers’ Party).
Before 1934, the Nazis had a paramilitary wing called the Sturmabteilung (SA). Their primary purposes were to provide protection for Nazi rallies and assemblies, to disrupt the meetings of opposing parties and to fight against the paramilitary units of the opposing parties. After 1934, the SA was turned into the SS (Schutzstaffel).
One of the core tactics of the Nazis was widespread propaganda, which they used to advance their point of view. This propaganda often came in the form of rallies, radio broadcasts, posters and movies among other methods.